This invention relates to selectively inhibiting television receiving apparatus from recording programs, received as digital video data, which are not authorized for viewing.
Techniques have been proposed heretofore to permit viewers to selectively enable and disable television receiving apparatus to prevent unauthorized television programming from being recorded and/or reproduced. With the introduction of the digital image communication systems such as the digital cable TV (CATV) systems, many services can be provided that were previously unheard of with the conventional TV broadcasting and CATV systems. The digital CATV systems not only provide conventional TV images, but can provide such services as electronic mail and electronic banking.
In the digital image communication systems, image storage devices are preferably incorporated into a conventional television receiving apparatuses. This enables the viewer to watch a television program on a particular channel while simultaneously recording television programs then being broadcasted on other channels in the image storage device; which can be reproduced later by the viewer.
The digital cassette tape recorder (hereinafter referred to as digital VCR) performs processing, such as parity code addition, ECC, formatting, modulating and so forth on video signals that have been highly efficiently coded. Thereafter, one or more rotating heads of the digital cassette tape recorder records the digital video signals on a magnetic tape. The digital cassette tape recorder also performs playback processing, such as demodulating, format decomposing, error correction and so forth on the signals played back from the magnetic tape so as to reproduce the digital video signals.
The digital cassette tape recorder may be incorporated into a conventional television receiver or into a decoder of the type typically used in cable television or direct satellite broadcast systems. Such decoders or converters are known and, consistent with industry usage, are referred to herein, as set-top converters.
In addition, in the digital CATV system, data in which a plurality of programs have been time-division multiplexed are transmitted. Normally, one program channel is selected by a television receiving device to display or store the program on that selected channel. However, programs broadcast on other channels at the same time as the selected program cannot be viewed or recorded for later viewing by that television receiving device. Thus, it is desirable to record those programs so they can be viewed later by the subscriber.
It is also desirable to record programs, such as movies, feature presentations, pay-per-view, etc., transmitted from the source during off-hours, e.g., midnight, so those programs subsequently can be viewed by the subscriber upon receiving proper authorization.